'True-blue' definitions:

Definition of 'true-blue'

(from WordNet)
adjective
Marked by unswerving loyalty; "a true-blue American"; "a reliable true-blue country club conservative"

Definition of 'True-blue'

From: GCIDE
  • True-blue \True"-blue`\, a. Of inflexible honesty and fidelity; -- a term derived from the true, or Coventry, blue, formerly celebrated for its unchanging color. See True blue, under Blue. [1913 Webster]

Definition of 'True-blue'

From: GCIDE
  • True-blue \True"-blue`\, n. A person of inflexible integrity or fidelity. [1913 Webster]